IMO TR is already included in PR calculation. but as it is presented in the paper it is the yahoo proposal for their own PR
Actually, that would be a reason for G to get rid of it, as buying links is a artifical manipulation of the SERPs...
By definition, PageRank is Google's measure of the importance of a page. It is the only thing which separates Google from the other search engines. And, by the way, PageRank most definitely makes a difference in the SERPs, it's just not the number one factor which gets a page to the top. Bompa
A page with poor PR is not even fully indexed, specially if it has many sub pages. MSN and Yahoo also have something similar, but they don't make it public.